fix: new language source file for activitypub text

public/language/en-GB/activitypub.json

@@ -0,0 +1,6 @@
+{
+	"no-topics": "This forum doesn't know of any other topics yet.",
+
+	"topic-event-announce-ago": "%1 shared <a href=\"%2\">this post</a> %3",
+	"topic-event-announce-on": "%1 shared <a href=\"%2\">this post</a> on %3"
+}

public/language/en-GB/admin/settings/activitypub.json

@@ -1,6 +1,4 @@
 {
-	"no-topics": "This forum doesn't know of any other topics yet.",
-
 	"acp.intro-lead": "What is Federation?",
 	"acp.intro-body": "NodeBB is able to communicate with other NodeBB instances that support it. This is achieved through a protocol called <a href=\"https://activitypub.rocks/\">ActivityPub</a>. If enabled, NodeBB will also be able to communicate with other apps and websites that use ActivityPub (e.g. Mastodon, Peertube, etc.)",
 	"acp.general": "General",

public/language/en-GB/error.json

@@ -282,5 +282,6 @@
 	"activitypub.invalid-id": "Unable to resolve the input id, likely as it is malformed.",
 	"activitypub.get-failed": "Unable to retrieve the specified resource.",
 	"activitypub.pubKey-not-found": "Unable to resolve public key, so payload verification cannot take place.",
-	"activitypub.origin-mismatch": "The received object's origin does not match the sender's origin"
+	"activitypub.origin-mismatch": "The received object's origin does not match the sender's origin",
+	"activitypub.actor-mismatch": "The received activity is being carried out by an actor that is different from expected."
 }